Realization of Paleopolyploidy through Cytogenetic and Phylogenetic Characterization of Ten Species of Senna Mill., Fabaceae-Caesalpinioideae

Abstract

Taxonomically and phylogenetically Senna species complex is quite intriguing having several status and origin related issues. Keeping this view in mind and scope of cytological investigation 10 species of same genus viz. S. alata, S. alexandrina, S. italica, S. obtusifolia, S. occidentalis, S. polyphylla, S. siamea, S. sulfurea, S. surattensis and S. tora were analysed in cytological frame and comprehensive data/ information, is generated. The basic chromosomal analysis revealed regular meiotic behavior despite the occurrence of some irregularities. The regular occurrence of multivalents especially quadrivalents at diplotene as well as diakinesis stage and unavailability of individual having x=7 chromosome number possibly indicates paleopolyploid origin of worked out taxa. Individual anther basis pollen analysis provides some clues regarding on going evolutionary processes in the same genus. Considered cytological parameters based cluster analysis and their comparison with molecular marker based phylogenetic analysis of earlier workers revealed the efficacy of used parameters in phylogenetic characterization of Senna species complex.

Male meiosis, sporad analysis and pollen viability in a threatened medicinal plant Oroxylum indicum (L.) Kurz

“…The percentage of abnormal PMCs was found to be on the higher side for V-6 (12.90%) and on the lower side for A-2 (2.81). As evolution is directly proportional to genetic recombination, the presence of a higher percentage of ring bivalents than those of rod bivalents and the existence of higher chiasma frequency per chromosome indicates that O. indicum possesses a good genetic recombination potential (Table 1) indicating an ongoing evolutionary process (Verma et al, 2020).…”

“…Percentage pollen fertility was estimated on basis of the ratio of stained pollen grains against total pollen grains analyzed. The pollen germination percentage was evaluated using the sucrose 30 % solution method (Verma et al, 2020). All data were recorded in replicates and statistically analysed using SPSS software.…”